Ok I have a 2003 2.7T Audi A6. It started to get a little bit of a rough idle, and then the car has rpm drop which nearly stalls the car out at a stop light. This does not happen all the time but every once an awhile. It is definelty not running right, but throws no codes or lights. If i put the car in park and rev the engine. When I let of the pedal the rpm drops, it drops to far and feels like the car is going to stall. I unplugged the MAF and it still idled the same way. I have no smoke or anything coming from the tailpipes. Does anyone have any ideas what it might be. I replaced the spark plugs thinking the slight misfire was from that, but it didnt help.

THANKS

 

BOOST LEAK